Thermoelectric control and safety shutoff device



July 2 1942. G. WUNSCH EI'AL THERMOELECTRIG CONTROL AND SAFETY SHUTOFF DEVICE Original Filed Aug. 5, 1934 Patented July 28, 1942 STATE iii THERMOELECTRIC CONTROL AND SAFETY SHUTOFF DEVICE Guido Wiinsch, Berlin-Steglitz, and Josef Schuppert, Dessau, Germany, ass'ignors, by mesne assignments, to Junkers 8; 00., G. in. b. H., Dessau, Germany, a company of Germany Application February 16, 1939, Serial No. 256,640,

which is a division of application Serial No.

738,370, August 3, 1934. Divided and this application October 30, 1940, Serial No. 363,474. In Germany September 28, 1933.

10 ()laims.

This invention relates to safety devices for heating and other apparatus and has particular relation to a thermoelectric control and safety shutofi device for gas and other fuel burners.

The present application constitutes a division of our copending application Serial No. 256,640, filed February 16, 1939, which latter application was copending with and a division of our application Serial No. 738,370, filed August 3, 1934, which latter application issued February 13, 1940 as Patent No. 2,189,829.

Due to the minute character of the maximum E. M. F. that can be generated by the heat of a pilot light or other flame or source of heat on a thermocouple and the inability of this minute thermoelectric current to actuate the main shutofi" valve from closed position to open position, thermoelectric control and safety shutoff devices prior to the present invention have required manual cocking or reset means, such as a cocking or reset button, for cooking or resetting the main shutoff valve to open position after each operation of this valve to closed position.

As a result, prior to this invention, these devices have not and could not be automatic or completely self-operating. For example, if a thermostat or other control device was employed for opening 'or disabling the thermoelectric circuit for operation of the valve to closed position at one predetermined temperature and for closing or rendering the thermoelectric circuit operative at another temperature, the closing or rendering operative of the thermoelectric circuit-with the pilot light or other flame burning and heating the thermocouplewould not open the main valve because the minute character of the thermoelectric current could not accomplish that result. v

Consequently it has been necessary to reset the shutofi valve to open position not only after the failure of the pilot or other flame or source of heat but also after each closing of the valve by the thermostat or other control means.

One of the main objects of the present invention is to elimhiate the necessity of manual cocking or reset means and the necessity of a manual cooking or resetting operation, and' to provide a thermoelectric control and safety shutoff device which is actuated to open position as well as held in open position through the instrumentality of the minute thermoelectric current, and which, therefore, is completely automatic or self-operating.

We have found that by employing a diaphragm or equivalent valve in the main fuel supply pipe (c1. its-417.1)

leading to the burner, with means for bleeding a minute quantity of fuel into the diaphragm or equivalent chamber from the fuel supply pipe anterior of the valve and for venting the diaphragm chamber, and by combining the thermoelectric control with this bleeding and vent means, we can, because of the much smaller size and lighter weight of this latter valve or control means, actually actuate this valve or control means from one position to another position, and that by. reason of this new combination we can for the first time, automatically establish and maintain the supply of fuel to the burner through the instrumentality of the minute thermoelectric current generated by the heat of thepllot light or other flame on the thermocouple. This is another and more specific feature of the present invcntion.

The burner may be the burner for a room or space heater, water heater floor funace, or it may be the burner or burners constituting the top burners of a gas range, or oven burners, or it may be' any other burner.

Further features and advantages of the invention will be apparent from the following detailed description, taken in connection with the accompanying drawing, in which the single figure is a diagrammatic view, partially in section, showing one illustrative embodiment of the invention.

Referring to the drawing, the diaphragm chamber I0 is divided by'a diaphragm ll into a first chamber or compartment I2 for connection with the fuel supply pipe l3, and a second chain her or compartment [4. The diaphragm ll carries a valve l5 for controlling the flow of fuel to the main burner. I

The burner l 6 may be any suitable or preferred burner as heretofore mentioned, for example the 40 main burner for a room or space heater, or it may be a burner for a water beaten-pr for a floor furnace, an oven burner, or one or more top burners of a gas range, or any other burner. The burner l5 receives the gas or other fuel from a suitable source of supply (not shown) through ,a suitable pass-age comprising a pipe I8 which communicates by a port or valve opening 20 with the diaphragm chamber I 2 situated below the diaphragm H as the apparatus is viewed in the drawing.

Gas or other fuel is supplied to the diaphragm chamber l2 through the fuel supply pipe l3. The port or valve opening 29 is adapted to be closed by the valve l5 to shut off the supply of fuel to the burner I 6. A restricted port or passage is provided at 2i for bleeding fuel from the fuel supply pipe |3 and, speciflcally, in the illustrated embodiment of the invention, from the diaphragm chamber |2 tothe diaphragm chamber M for the purpose of equalizing the pressure above and below the diaphragm H, or permitting building up of pressure in the diaphragm chamber l4 sumcient to cause movement of the valve I5 to position closing the port or opening 2!] to shut off the supply of fuel to the burner I6 upon extinguishment of the pilot flame, as will hereinafter more fully appear.

A pipe 24, shown partly diagrammatically, conveys a partial or restricted supply of gas or other fuel from the diaphragm chamber M to a valve chamber 25 containing a valve or controlling member 26 and a valve seat surrounding a port or valve opening. The control body having the valve chamber 25 is provided with an electromagnet 28 for opening and holding the valve member 26 in open or operating position, as shown. The electromagnet comprises a magnet frame and an electromagnetic coil, as more fully disclosed in our application Serial No. 738,370, filed August 3, 1934, which issued February 13, 1940, as Patent No. 2,189,829, or the electromagnet may be of any other suitable or preferred form. The 'electromagnet is connected in circuit, as more or less diagrammatically illustrated at 29, with a thermocouple or multiple thermocouple or thermopile 30.

The thermocouple or multiple thermocouple device 30 is placed in position to be heated by a pilot light 32. The thermocouple or multiple thermocouple device 36 and the thermoelectric circuit may be constructed and operated substantially the same as similar parts described in our Patent No. 2,189,829, or they may be constructed and operated in any other suitable or preferred manner.

The pilot light 32 receives gas or other fuel from the fuel supply pipe l8 preferably through a pipe 34 connected to the diaphragm chamber |2 anterior of the valve port r opening 20 as shown at 35. A valve 36 may be provided in the pipe 34. The outlet from the valve chamber 25 leads to a burner 38. Gas or other fuel issuing from the burner 38 is adapted to be ignited by the pilot light 32 to form a flame or pilot 39 for igniting the main burner I6.

In the thermoelectric circuit 29 means is pro-v vided to open said circuit or otherwise to render the same inoperative, said means being shown, for purposes of illustration, as comprising a switch including two members 60 and 62 normally contacting to close the circuit for the thermoelectric current set up by the thermocouple means at 30, but one of which is controlled by a thermostat or heat responsive means shown for illustrative purposes as comprising an expansible member 63 extending, for example, into the container 64 for the liquid to be heated by the burner IS. The adjustment of the thermostat or heat responsive means and switch is such that as long as the temperature of the liquid within the container 64 does not exceed the safety point or that desired, the switch will remain closed, but, in the contrary case-that is, when the temperature of the liquid exceeds the desired or permissible temperature-the switch will be operated to open or break the thermoelectric circuit 29 and allow the valve 26 to move to closed position.

The closing of the valve 26 by the opening or rendering inoperative of the thermoelectric circuit by the thermostat or equivalent means shuts off the flow or escape of fuel from the upper diaphragm chamber M to the pilot 39. The diaphragm chamber M, or the space above the diaphragm II, will then become filled with fuel through the port or passage 2| and the fuel pressure will become equalized above and below the diaphragm H, or will build up sufficiently to cause movement of the valve J5 to closed position shutting off the supply of fuel to the bumer l6.

As long as the pilot light 32 remains lighted and the thermostat controlled switch is closed, the electromagne-t 28 will be energized by the resulting thermoelectric current and will hold the valve or controlling member 26 in open or operating position. Gas or other fuel passing through the restricted or bleed port or passage 2| and into the diaphragm chamber l4 escapes through the pipe 24, the valve opening surrounded by the valve seat 21, and through the jet or burner 38 to supply the flame or pilot 39, and the diaphragm II and valve |5 will thus be held in raised or open position by the gas or fuel pressure on the under side of the diaphragm. The main burner I6 is thus supplied with fuel which will be ignited by the flame 39.

Should the pilot light 32 become extinguished due to insuficient fuel supply or due to a draft, or for any other reason, the electromagnet 28 becomes deenergized owing to the failure of the thermoelectric current, and the valve or controlling member 26 moves to closed position closing the port or valve opening surrounded by the valve seat 2'! and shutting off the flow or escape of fuel from the diaphragm chamber M to the pilot 39. The diaphragm compartment l4, or the space above the diaphragm II, will then become filled with fuel through the port or passage 2|, and the fuel pressure will become equalized above and below the diaphragm, or will build up in the chamber l4 sufficiently for movement of the valve IE to closed position. valve member IE will then drop or move into closed position engaging the valve seat surrounding the port or valve opening 20, thus shutting off the supply of fuel to the burner I6.

The construction shown and described has the advantage in that the valve l5 will be reopened as soon as the thermostat closes the thermoelectric circuit because, in the illustrated apparatus,

when the temperature again drops below the danger point, switch member 60, 62 will again contact, and, assuming that the pilot light is burning, the thermoelectric current will again energize the electromagnet, thus reopening the relatively small and relatively light weight valve 26, the stroke of said valve being so short (a few millimeters only)" that the magnetism created in the magnet part of the electromagnet by the thermoelectric current will suffice to attract the valve 26 and raise it from closed to open position.

Upon the occurrence of this self-operation of the valve 26 to open position, the gas or other fuel passing through the restricted or bleed port or passage 2| and-into the diaphragm compartment l4 escapes through the pipe 24, the valve opening surrounded by the valve seat 21, and through the jet or burner 38 to supply the flame or pilot 39, and the diaphragm II and valve l5 are operated to raised or open position by the gas or fuel pressure on the under side of the diaphragm.

The thermostat is thus operable when the thermocouple is heated by the pilot light to render Thethe thermoelectric circuit operative automatically to actuate the valve or control means 26 to and to hold same in a first position and to disable the thermoelectric circuit for operation of this valve or control means 26 to its second position at different predetermined temperatures, and the apparatus is thus operable automatically not only to maintain, but actually to establish the supply of fuel to the burner l6 through the instrumentality of the minute thermoelectric current generated by the heat of the pilot light on the thermocouple means.

It will further be apparent that with the thermostat controlled switch closed, the application of the heat of the pilot flame to the thermocouple means upon relighting the pilot burner after extinction thereof will operate the valve or control member 26 to open or operative position, with a resulting automatic opening of the valve I through the instrumentality of the minute thermoelectric current generated by the heat of the pilot light on the thermocouple.

The embodiment of the invention shown in the drawing is for illustrative purposes only, and

it is to be expressly understood that said drawing and the accompanying specification are not to be construed as a definition of the limits or scope of the'invention, reference being had to the ap.- pended claims for that purpose.

We claim:

1. In a thermoelectric control apparatus for a burner, the combination with a burner, a fuel supply pipe leading to said burner, a pilot light in position to ignite said burner, and a thermocouple placed in position to be heated by said pilot light, of means operable automatically to establish and maintain the supply of fuel to said burner through the instrumentality of the minute thermoelectric current generated by the heat of the pilot light on said thermocouple and comprising a diaphragm valve in the fuel supply pipe leading to said burner, said valve having a valve seat on one side of the diaphragm and a diaphragm provided with a valve member cooperable with said seat, a diaphragm chamber for the opposite side of the diaphragm, means for a burner, the' combination with a burner, a fuel supply pipe leading to said burner, a pilot light in position to ignite said burner, and a thermocouple placed in position to be heated by said pilot light, of means operable automatically to establish and maintain the supply of fuel to said burner through the instrumentality of the minute thermoelectric current generated by the heat of the pilot light on said thermocouple and comprising a diaphragm valve in the fuel supply pipe leading to said burner, said valve having a valve seat on one side of the diaphragm and a diaphragm provided with a valve member cooperable With said seat, a diaphragm chamber for the opposite side of the diaphragm, means for bleeding fuel into said diaphragm chamber from the fuel supply pipe anterior of said valve and for venting said diaphragm chamber, control means for said vent means, an electromagnet connected in circuit with said thermocouple and operable by the thermoelectric current generated by the heat of the pilot light on the thermocouple to actuate said control means to and to hold same in a first position for venting the fuel from said diaphragm chamber and for preventing building up of pressure in'said diaphragm chamber to permit said diaphragm valve to be opened and held open by the pressure of the fuel in said fuel supply pipe on the anterior side of said valve seat, said control means being operable upon extinction of the pilot light to a second position shutting 01f the venting of fuel from said dia phragm chamber and permitting building up of pressure in said chamber sufficient to cause movement of said valve to closed position, and a thermostatoperable when the thermocouple is heated bleeding fuel into said diaphragm chamber from a the fuel supply pipe anterior of said valve and for venting said diaphragm chamber, control means for said vent means, an electromagnet connected in circuit with said thermocouple and operable by the thermoelectric current generated by the heat of the pilot light on the thermocouple to actuate said control means to and to hold same in a first position for venting the fuel from said diaphragm chamber and for preventing building up of pressure in saiddiaphragm chamber to permit said diaphragm valve to be opened and held open by the pressure of the fuel in said fuel supply pipe on the anterior side of said valve seat, said control means being operable upon extinction of the pilot light to a second position shutting off the venting of fuel from said diaphragm chamber and permitting building up of pressure in said chamber sufiicient' to cause movement of said valve to closed position, and a thermostat operable when the thermocouple is heated by the pilot light to render said thermoelectric circuit operative automatically to actuate said control means to and to hold same in said first position and to disable said thermoelectric circuit for operation of said control means to said second position at different predetermined temperatures.

by the pilot light to render said thermoelectric circuit operative automatically to actuate said control means to and to hold same in said first position and to disable said thermoelectric circuit for operation of said control means to said second position at different predetermined temperatures, said thermostat being connected directly into the thermoelectric circuit including said thermocouple and said electromagnet.

3. In thermoelectric control apparatus for a burner, the combination with a burner, a fuel supply pipe leading to said burner, a pilot light in position to ignite said burner, and a thermocouple placed in position to be heated by said pilot light, of means operable automatically to establish and maintain the supply of fuel to said burner through the instrumentality of the minute thermoelectric current generated by the heat of the pilot light on said thermocouple and comprising a diaphragm valve in the fuel supply pipe leading to said burner, said valve having a valve seat on one side of the diaphragm and a diaphragm provided with a valve member cooperable with said seat, a diaphragm chamber for the opposite side of the diaphragm, means for bleeding fuel into said diaphragm chamber from the fuel supply pipe anterior of said valve and for venting said diaphragm chamber, control means for said Vent means and an electromagnet connected in circuit with said thermocouple and operable by the thermoelectric current generated by the heat of the pilot light on the thermocouple to actuate said control means to and to-hold same in a first posi-- tion for venting the fuel from said diaphragm chamber and for preventing building up of pressure in said diaphragm chamber to permit said diaphragm valve to be opened and held open by the pressure of the fuel in said fuel supply pipe on the anterior side of said valve seat, said control means being operable upon extinction of the pilot light to a second position shutting off the venting of fuel from said diaphragm chamber and permitting building up of pressure in said cham--: ber sufficient to cause movement of said'valve to closed position.

' I 4, In thermoelectric control apparatus for a;- burner, the combination with a burner, a fuelsupply pipe leading to said burner, and a thermocouple placed in position to be heated by a flame,

of means operable automatically to establish and maintain the supply offuel to said burner through I the instrumentalityof the minute thermoelectric current generated by the heat of the flame on said I thermocouple and comprising a; diaphragm valve in the fuel supply pipe leading to said burner,

said valve having a valve seat on one'side of' th'e I diaphragm and a diaphragm provided with a valve member cooperablewith said seat, a diaphragm chamber for the opposite side of 'the'diaphragm, means for bleeding fuel into said diaphragm chamber from the fuel supply pipe anterior of said valve and for venting said dia phragm chamber, control -means for said vent means, an electromagnet connected in circuit t with said thermocouple and operable by the then moelectric current generated by the heat of the flame onv the thermocouple to actuate said control means to and to hold same in a first posi- 1 tion for venting the fuel from said diaphragm chamber and 'for'preventing building up of pressure in said diaphragm chamber to permit said diaphragm valve to be opened 'and held open by thepressure of fuel in said fuel supply pipe on the anterior side of said valve seat, said control means being operable upon extinction of the fiame to a second position shutting off the venting of fuel from said diaphragm chamber and permitting burner, the combination with a burner, a fuel supply pipe leading to said burner, a pilot light in position to ignite said burner, a thermocouple placed in position to be heated by said pilot light, of means operable automatically to establish and maintain the, supply of fuel to said burner through the instrumentality of the minute thermoelectric current generated by the heat of the pilot light on said thermocouple and comprising a diaphragm valve inithe fuel supply pipe leading to said burner, said valve having a valve seat on one side of the diaphragm and a diaphragm provided with a valve member cooperable with said seat, a diaphragm chamber for the opposite side of the diaphragm, means for bleeding fuel into said diaphragm chamber from the fuel supply pipe anterior of said valve and for venting said diaphragm chamber, control means having a first position for venting the fuel from said diaphragm chamber and preventing building up of pressure in said diaphragm chamber to permit said diaphragm valve to be opened and held open by the pressure of fuel in said fuel supply pipe on the anterior side of said valve seat, said control means having a second position shutting off the venting circuit with'said thermocouple and operable by the thermoelectric current generated by the heat I of the pilot light on the thermocouple to actuate said control means'to and to hold same in said first position, said control means being operable vtrol means to said second position at different BUY Cal

predetermined temperatures. I 1 I 6. In thermoelectric control apparatus for a burner, the combination with a burner, a fuel supply pipe leading to 'saidburneiya' pilot light I in position to ignite said burner, a thermocouple placed in position to be heated by said pilot light,

of means operable automatically to establish and I maintain the supply of fuel. to said burner through, the instrumentality of the minute thermoelectric current generated by'the' heat of the pilot light on said thermocouple and comprising a diaphragm valve in the fuel supply pipe leading to said burner, saidvalve havinga valve seat on one side of the diaphragmand a diaphragm provided with a valve member cooperable with said seat, a diaphragm-chamber for the opposite side of the diaphragm, means for bleeding fuel into said diaphragm chamber from the fuel supply pipe anterior of said valve and for venting said dia-" phragm chamber, control means having a first chamber and preventing building up'of pressure in said diaphragm chamber to permit said diaphragm valve to be opened and held open by the pressure of fuel in said fuel supply pipe on the anterior side of said valve seat, said control means having a second position shutting off the venting of fuel from said diaphragm chamber and permitting building up of pressure in said chamber sufficient to cause movement of said valve to closed position, and an electromagnet connected in circuit with said thermocouple and operable by the thermoelectric current generated by the heat of the pilot light on the thermocouple to actuate said control means to and to hold same in said first position, said control means being operable upon extinction of the pilot light to said second position.

'7. In thermoelectric control apparatus for a burner, the combination with a burner, a fuel supply pipe leading to said burner, a pilot light in position to ignite said burner, a thermocouple placed in position to be heated by said pilot light, of means operable automatically to establish and maintain the supply of fuel to said burner through the instrumentality of the minute thermoelectric current generated by the heat of the pilot light on said thermocouple and comprising a diaphragm valve in the fuel supply pipe leading to said burner, said valve having a valve seat on one side of the diaphragm and a diaphrgm provided with a valve member cooperable with said seat, a diaphragm chamber for the opposite side of the diaphragm, means for bleeding fuel into said diaphragm chamber from the fuel supply pipe anterior of said valve and for venting said diaphragm chambencontrol means having a first position for venting the fuel from said diaphragm chamber and preventing building up of pressure in said diaphragm chamber to permit said diaphragm valve to be opened and held open by the pressure of fuel in said fuel supply pipe on the anterior side of said valve seat, said control means having a second position shutting off the venting of fuel from said diaphragm chamber and permitting building up of pressure in said chamber sufiicient to cause movement of said valve to closed position, an electromagnet connected in circuit with saidthermocouple and operable by the thermoelectric current generated by the heat of the pilot light on the thermocouple to actuate said control means to and to hold same in said first position, said control means being operable upon extinction of the pilot light to said second position, and an on and off switch connected in circuit with said thermocouple means and said I electromagnet and operable automatically at a preselected point to disable the thermoelectric circuit including said thermocouple means and said valve.

8. In thermoelectric control apparatus for a burner, the combination with a burner, a fuel sup- I ply pipe leading to said burner, a pilot light in position to ignite said burner, a thermocouple placed in position to be heated by said pilot light, of means operable automatically to establish and maintain the supply of fuel to said burner through the instrumentality of the minute thermoelectric current generated by the heat of the pilot light on said thermocouple and comprising a diaphragm valve in the fuel supply pipe leading to said burner, said valve having a valve seat on one side of the diaphragm and a diaphragm provided with a valve member cooperable with said seat, a diaphragm chamber for the opposite side of the diaphragm, means for bleeding fuel into said diaphragm chamber from the fuel supply having a second position shutting 01f the venting of fuel from said diaphragm chamber and permitting building up of pressure in said chamber sufficient to cause movement of said valve to closed position, an electromagnet connected in circuit with said thermocouple and operable by the thermoelectric current generated by the heat of the pilot light; on the thermocouple to actuate said control means to and to hold same in said first position, said control means being operable upon extinction of the pilot light to said second position, and a switch operable to on and off positions to render said thermoelectric circuit operative automatically to actuate said control means to and to hold same in said first position when the thermocouple is heated by the pilot light and operable to disable said thermoelectric circuit for operation of said control means to said second position.

9. In burner control apparatus, the combination with a burner, of ignition means for igniting the fuel at the'burner, automatic shutoff valve means for shutting off the flow of fuel\ to the burner, an electromagnet, a thermoelectric generator adapted to be subjected to the heat of said ignition means and connected in circuit with the electromagnet for energizing said electromagnet by the heat of said ignition means, the energization of said electromagnet by the heat of said ignition means on said thermoelectric generator being in itself incapable of opening said automatic shutoff valve, means supplementary to and operating in conjunction with said electromagnet and its connected thermoelectric generator to open said automatic shutoff valve upon energiza tion of said electromagnet by the heat of the ignition means on said thermoelectric generator, and automatically operable switch means connected into the thermoelectric circuit including said themoelectric generator and said electromagnet for automatically opening and closing said thermoelectric circuit. I

10. In burner control apparatus, the comb-ination with a burner, of ignition means for igniting the fuel at the burner, automatic shutoff valve means for shutting off the flow of fuel to the burner, an electromagnet, a thermoelectric generator adapted to be subjected to the heat of said ignition means and connected in circuit with the electromagnet for energizing said electromagnet by the heat of said ignition means, the energization of said electromagnet by the heat of said ignition means on said thermoelectric generator being in itself incapable of opening said automatic shutoff valve, means supplementary to and operating in conjunction with said electromagnet and its connected thermoelectric generator toopen said automatic shutoif valve upon energization of said electromagnet by the heat of the ignition means on said thermoelectric generator, automatically operable switch means connected into the thermoelectric circuit including said thermoelectric generator and said electromagnet 

